Currently, superimposed pictures can be produced only in an expensive and cumbersome manner. Specifically, at least one cut negative film for one or more elements of the final composition is first exposed, with the element(s) to be photographed being cast against a black background (or using a special mask permitting only the element(s) to be "seen" by the lens). The black background will not cause exposure but will result in a transparent area on the exposed, developed negative. A second negative is similarly prepared for the background. The second negative also contains an unexposed portion corresponding to the exposed portion of the first negative(s). The two cut negatives are then superimposed in "sandwich contact" together with the positive substrate and the positive print is generated.
It is obvious that this is an expensive technique requiring use of cut film and involving at least two negatives, substantial manipulation of the negatives and a long processing which must be conducted manually. In addition, the cut negative films and the positive (final) print must be of the same size and in contact with each other for optimum results. Cut negative is professional film and therefore very expensive. Roll film cannot be used. Furthermore, the degree of exposure of the first negative and of the second negative should be identical for optimum results in the composite picture, and hence a substantial amount of skill in the photographic art is required.
In the field of photography, it is often desirable to have a uniform light field to illuminate the object to be photographed. This becomes more important when the object to be photographed is of small dimensions and has considerable detail that must be reproduced on the photograph (such as for example an electronic chip, a stamp and the like) or if the object to be photographed or reproduced is not flat and smooth but has surface abnormalities (such as an antique photograph or a photograph that has creases). In the prior art, such objects were illuminated directly with two or more lights cast from different directions and angles. Although this represented an improvement over the use of a single light source, a uniformly lit field was not achievable. Multiple light sources had to be used and umbrellas and/or reflectors were also used to soften the light and to make it more evenly distributed. In spite of these efforts, the light field was far from uniform. Also, the body of the photographer and the apparatus cast a shadow further contributing to the non-uniformity of the light field. In addition, careful adjustment of the multiple light sources and other aids was necessary and several measurements of light intensity with a light meter were indispensable with each adjustment. All this was time consuming and added to the expense of the photography operation. The equipment costs were also considerable.
In other photographic applications, it is often desirable to take a picture of an object against a different background. In photographic studios, this can be achieved by having a painted background depicting the image or design desired or a screen on which the background can be projected, and placing the subject to be photographed against this background in front of the screen. If a projector is used, the projector projecting the image of the background on the screen is usually located behind the screen (although it could also be located in front of the screen, but that requires use of expensive additional equipment). The projector is of course equipped with a light source.
In front of the screen, more than one light source is necessary to illuminate the subject in the foreground. The same types of problems with regulating the intensity and uniformity of the light are present here. In addition, this operation also requires expensive equipment (the screen or backdrop must be of sufficient size to accommodate the subject in the foreground, etc.) and substantial time in preparation of the photographic session.